Sansui 517 Restore

I made my first Sansui purchase and picked up a Sansui AU-517 from eBay. When it arrived, it has static and a weak signal in the left channel (the right channel is fine). Connecting a sound source to the power amp in connections does not have any effect on the left channel. I cleaned all the pots using Deoxit and the static/weak signal remains.

Does anyone have any suggestions on how to fix this type of problem?

As part of an initial repair/upgrade process, I have removed the power supply and XXX boards to remove the corrosive glue and will be replacing all the electrolytic capacitors.

I have seen some common themes in posts in this board that certain parts should be replaced to improve the longevity of this amp, such 1) Power Relay, 2) trimmers, 3) large capacitors, 4) zener diodes, 5) fuse resistors, and 6) transistors. I would really appreciate some help with finding the product numbers of these replacement parts (Digi-Key part numbers would be really helpful). If anyone has any further knowledge or guidance they would like to share, I would appreciate their input.

1) I found a Omrom power relay mentioned in a post for the AU-717: Digi-Key part number Z2634-ND, manufacturer part number MY4-02-DC24. Is this the same part for the AU-517?

2) The trimmers on the boards are labeled VR1 (78d - 1KΩ8) , VR2 (78d- 2.2KΩ8) & VR3(79r-100Ω8). Which Bourne trimmers can replace these?

3) Replacing the large capacitors (63v, 12000uF): Possible replacement options I have found are Nichicon Gold 15000uF from Michael Percy Audio ($23.95 each) or Panasonic 63V 15000uF TUP from Digikey ($11.31 each). Is there a difference in sound quality when choosing either of these capacitors or are there better choices?

sschill said:

I made my first Sansui purchase and picked up a Sansui AU-517 from eBay. When it arrived, it has static and a weak signal in the left channel (the right channel is fine). Connecting a sound source to the power amp in connections does not have any effect on the left channel. I cleaned all the pots using Deoxit and the static/weak signal remains.

Does anyone have any suggestions on how to fix this type of problem?

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This is very likely the infamous R23/R25 fuse resistors on the driver boards - change them for metal film replacements ¼ or ½ watt rating but no more.

sschill said:

As part of an initial repair/upgrade process, I have removed the power supply and XXX boards to remove the corrosive glue and will be replacing all the electrolytic capacitors.

Click to expand...

Total glue removal is an absolute must, and replace any component touched by it - this might include resistors and diodes in addition to the electrolytic capacitors.

sschill said:

I have seen some common themes in posts in this board that certain parts should be replaced to improve the longevity of this amp, such 1) Power Relay, 2) trimmers, 3) large capacitors, 4) zener diodes, 5) fuse resistors, and 6) transistors. I would really appreciate some help with finding the product numbers of these replacement parts (Digi-Key part numbers would be really helpful). If anyone has any further knowledge or guidance they would like to share, I would appreciate their input.

Click to expand...

Electrolytic capacitors = yes
Resistors = fuse resistors= yes
Relay = maybe
Trimmers = yes
Zener diodes = yes
Large (main x4) capacitors = maybe / maybe not
Transistors = no, unless they are clearly below par - the one and only transistor you should replace is the relay driver transistor.

sschill said:

1) I found a Omrom power relay mentioned in a post for the AU-717: Digi-Key part number Z2634-ND, manufacturer part number MY4-02-DC24. Is this the same part for the AU-517?

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It is common to find that you don't need to replace this relay, however, if you have the money to spare it can't hurt - correct type quoted BTW (same for AU-717)

sschill said:

2) The trimmers on the boards are labeled VR1 (78d - 1KΩ8) , VR2 (78d- 2.2KΩ8) & VR3(79r-100Ω8). Which Bourne trimmers can replace these?

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I might be able to find the type numbers I used here.

sschill said:

3) Replacing the large capacitors (63v, 12000uF): Possible replacement options I have found are Nichicon Gold 15000uF from Michael Percy Audio ($23.95 each) or Panasonic 63V 15000uF TUP from Digikey ($11.31 each). Is there a difference in sound quality when choosing either of these capacitors or are there better choices?

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Unless they are actually leaking or showing other signs of obvious failure, I would hold off on replacing the main capacitors at the outset. Wait until you have done the rest - these capacitors last well. I changed mine (AU-717) and hardly noticed the difference - I used the Michael Percy ones - these are the only ones to use unless you are on a budget.

sschill said:

2) The trimmers on the boards are labeled VR1 (78d - 1KΩ8) , VR2 (78d- 2.2KΩ8) & VR3(79r-100Ω8). Which Bourne trimmers can replace these?

Click to expand...

Following up on this, here are the trimmer details

1KΩ = Bourns type 3296P Side Adj Trimmer 10mm.
2.2KΩ = 2KΩ = Bourns type 3296P Side Adj Trimmer 10mm.
100Ω = Bourns type 3296P Side Adj Trimmer 10mm.

These are all 25 Turn types - some say this is too many adjustment turns and is thus too fiddly. I have not found this to be the case and appreciated the fineness of adjustment available from them. YMMV

John,

Thank you for your help. At the risk of sounding like a complete novice (which I am), which transistors are the relay driver transistors? Hopefully my questions will help out other new people as well.

I am having a hard time determining the colors on R13/R14 on the power supply board. They were both covered in glue and should be replaced. They could either be red red black gold (22k) or red red brown gold (220k). Can anyone help me confim the ohms for these resistors?

Thanks again for helping with my numerous questions. I'll let everyone know how things turn out once everything is put back together again.

Shannon

sschill said:

John,

Thank you for your help. At the risk of sounding like a complete novice (which I am), which transistors are the relay driver transistors? Hopefully my questions will help out other new people as well.

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Only one - TR603 (2SC945 -on PSU/protector PCB) - this transistor has a hard life, it is a good idea to replace it with same type or a Fairchild equivalent KSC945 (available from Mouser & others).

sschill said:

I am having a hard time determining the colors on R13/R14 on the power supply board. They were both covered in glue and should be replaced. They could either be red red black gold (22k) or red red brown gold (220k). Can anyone help me confim the ohms for these resistors?

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I can fully understand your difficulty with this - they are 22 ohm (red, red, black, (& gold = the tolerance = 5%) A good idea to replace all 4 while you are at it - R13, R15, R14, R16. - Do you have a schematic or full service manual? - this will help you immeasurably.

sschill said:

Thanks again for helping with my numerous questions. I'll let everyone know how things turn out once everything is put back together again.

Shannon

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Working perfectly!

Hi John,

Thank you so much for sharing your insights & knowledge. After removing all of the glue, changing out the fusing resistors & the electrolyctic capacitors on the power and driver boards, both channels sound perfect. I am looking forward to many hours of listening enjoyment.

Thanks again for your help.

sschill said:

Hi John,

Thank you so much for sharing your insights & knowledge. After removing all of the glue, changing out the fusing resistors & the electrolyctic capacitors on the power and driver boards, both channels sound perfect. I am looking forward to many hours of listening enjoyment.

Thanks again for your help.

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Hey I wanna thank John too - because I am temporarily the happy user of this fine Au-517 that Shannon ,who lives in the same sub, brough over for testing. Sadly it was highly distorted in one-channel out of the ebay box, but Shannon totally resurected the beast from its extemely dusty and overly sanglui condition to looking like new on the inside.

Boy it sounds good - smoother, darker and deeper than my restored Eight. Only leg up the Eight has is for its cleaner meaner punch and in your face dynamics. On some recordings it works on others its to unrefined - whereas the restored Au-517 consitently pours honey and weaves silk.

sschill said:

3) Replacing the large capacitors (63v, 12000uF): Possible replacement options I have found are Nichicon Gold 15000uF from Michael Percy Audio ($23.95 each) or Panasonic 63V 15000uF TUP from Digikey ($11.31 each). Is there a difference in sound quality when choosing either of these capacitors or are there better choices?

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apexjr.com has the 15000uf 63v THA Panasonic caps for $2.99ea which are 40mm x 50mm. These caps appear to be December 2009 build date though. I've got several sitting here that I will eventually get around to fitting to my AU-517.

Tom,

Glad to hear you're enjoying the smooth sounds of the 517. Thanks for your help with the dc current and bias settings!